1. Field of the Invention
The present invention relates to binding systems used to secure die-cut perforated sheets of paper within a holder, and more particularly to binder rings for securing and collating the paper sheets.
2. Description of the Related Art
Prior art binders include protruding locking ring notebooks, spiral ring notebooks, rotary wheels, tubular clips, hanging folders, and the like. Examples of prior art binders are disclosed in U.S. Pat. Nos. 2,413,078 (R. P. Scholfield), 1,027,523 (E. E. Buchman), 4,607,970 (Heusinkveld), 2,718,229 (F. F. Gregory), 2,249,064 (R. Tauber), 1,037,292 (L. M. Morden).
The prior art binding devices possess several inadequacies. For example, locking ring notebooks can only accommodate a single size paper, corresponding to the size of the ring mechanism. Locking ring notebooks cannot function as hanging folders for convenient storage. The bulky size of the rings restrict the movement of the pages, not allowing a user to easily flip through the bound pages since the binder rings tend to catch on the page penetrations. Moreover, locking ring binders do not permit the cover and interior pages to be folded back through a full 360.degree..
Spiral ring notebooks are also limited to a single size paper, cannot function as hanging folders for convenient storage, and leave behind a perforated section when the pages are removed.
Tubular clips and the like are too flimsy to be hung on a support disposed for example in a file drawer, thus precluding convenient storage. Moreover, pages bound with tubular clips do not lay flat, are difficult to fold back 360.degree., and are restricted in movement due to interference from the clip.
Hanging folders are relatively easy to store, and can lay flat for use, with easy unrestricted movement of the pages. However, such folders do not bind together the loose leaf pages contained therein.